Preparation of condensation products of acid anhydrides



PREPARATION OF CONDENSATION PRODUCTS OF ACID ANHYDRIDES Johannes Donatusvon Mikusch-Buchberg and Karlheinz Hermann Mebes, Hamburg-Harburg,Germany, assignors to Lever Brothers Company, New York, N.Y., acorporation of Maine No Drawing. Application October 1, 1956 Serial No.612,940

Claims priority, application Great Britain October 7, 1955 9 Claims. 01.26(l343.5)

. described a process for obtaining condensation products from fattyacids. It has now been found that useful condensation products may beobtained by heating fatty acid anhydrides, particularly anhydrides ofunsaturated fatty acids, at temperatures between 180 and 300 C.,provided that the water formed during the reaction is removed.

The present invention provides therefore a process for WQQ.

2 Fatty acids for use according to the invention have the formula R.COOH

where Rhas the same meaning as above. Suitable fatty acids are linoleicacid, linolenic acid, or the highly unsaturated acids occurring inmarine oils, such as herring oil, whale oil, pilchardoil, and sardineoil.

Fatty ketones" for use according to the invention have the formulaR.CO.R'

where .R and R have the same meaning as above and may be the same ordifferent.

Fatty acid anhydrides, fatty acids, or fatty ketones which contain onlyone double bond may be used in starting materials for the preparation ofcondensation products according to the invention but it is preferred touse at least a proportion of fattycompounds containing unsaturated alkylgroups with two or more double bonds.

The starting material may contain a minor proportion of otherconstituents such as, for example, fatty oils, mono-, dior triglyceridesor resin acids. These constituents have a tendency to slow down thedesired reaction andhence too great a proportion should be avoided.

The temperature and time of heating employed and the proportion ofunsaponifiable matter which can be obtained depend to somedegree on thetypes of fattyan- I hydrides, ,acids and ketones which are used asstarting thepreparation of condensation products which comprises heatinga non-hydroxylated fatty acid anhydride between 180 and"300 C. withremoval of the water'formed in the reaction until'the product contains asubstantial proportion of unsaponifiable matter having a mean molecularweight in accordance with that calculated for a. condensation product ofat least 3 molecules. of the fatty acid corresponding to the fattyacidanhydride.

The starting material may also contain fatty acidsin admixture with thefatty acid anhydride. The fatty acids maybe the same or different fattyacids as those from which the fatty acid anhydrides are derived. The.starting material may further contain fatty .ketones which may bederived from the same or different fatty acids as those from which thefatty acid anhydrides are derived. Fatty acid anhydrides for useaccording to the invention should have the formula where R and R arehydrocarbon groups, preferably long saturated or unsaturated hydrocarbonchains, which are preferably unsubstituted. The hydrocarbon chain mustnot contain hydroxyl groups. .It is preferred that R and R areunsaturated alkyl groups having a chain length of from.9 to'25 carbonatoms, the most preferred chain length being from 17 to 21 carbon atoms.Thus, fatty anhydrides containing from 20 to 52 carbon atoms arepreferred, most preferably from 36 to .44 carbon atoms. R.and:R .arepreferably identical,.but may bedifferent.

..;Examples of suitable fatty acid anhydrides are the fatty acidanhydrides derived from groundnut oil andthe anhydrides derivedfrom thetreatment of linseed oilfatty acids with acetic anhydride.

- materials.

Thus, with fatty compounds which have a relatively low iodine value,heating can be carried out at highternperatures for a long time and highproportions of unsaponifiable matter, for example 70% to nearly can beobtained. With' fatty compounds of high iodine, value, for example over150, heatingmay have to be discontinued earlier, since gelation may takeplace and the proportion of unsaponifiable matter may then be lower, forexample 40 to 60%.

According to the purposes for which it is desired to use thecondensation products of the invention the degree ofconversion of thefree fatty anhydrides to unsaponifiable matter having thecharacteristics specified may vary within wide limits. For certainpurposes, a degree of conversion of from 20 30%' .may'be suflicient,whilst for other purposes a degree of conversion of from 3040% may besufficient. It is preferred that the degree of conversion should be atleast 40%.

I The fatty compounds used as starting materials may, in some cases, bepurified with advantage according to the usualmethods.

It is preferred to have a catalyst present, particularly if substantialamounts of fatty acids or fatty ketones are present. The catalyst usedin the processes of the invention may be a boron compound. It ispreferred to use oxygen-containing boron compounds. Preferred inorganicboron compounds are boric acid and its derivatives and boric oxide.Boron salts such as, for example, the .alkali pentaborates, preferablyammonium pentaborate, may also be used with advantage. Borax has onlyslight activity as a catalyst, however. Boron compounds with oxidizingproperties may be undesirable.

Preferred organic boron compounds are the esters of boric acid, such asboric acid t-rimethyl ester, boric acid triethyl ester, and boric acidmannitol ester, the mixed anhydride of boric acid and acetic acid or themixed anhydride of boric acid and higher fatty acids such as areobtained, for example, from groundnut oil.

The catalyst may be supported on a suitable carrier, for example anoxide of silicon such as kieselguhr, diatomite or silica gel. When asupported catalyst is used the catalyst may be dissolved or suspended inwater and the carrier material added, the resultant mixture being driedin an oven.

The amount of catalyst may vary widely, for example, between 0.1% and byweight of the starting material. Generally, 0.1% to 2% is sufficientwhen mixtures containing a large proportion of fatty acid anhydride areused as starting materials. The catalyst may be mixed with the startingmaterial or added during the heating in the reaction vessel, or it canbe placed in the reflux column.

The mixture in the vessel is heated to temperatures between 180 and 300C. It is desirable to keep the reaction mixture at temperatures between240 and 300 C. for at least the latter part of the time during which thereaction is effected, especially if it is desired to obtain a productwith superior drying properties. The reaction may be carried out atatmospheric pressure, for example under an inert gas such as carbondioxide, but preferably under vacuum.

Heating is preferably carried out in such a manner that refluxing of thehigher boiling compounds occurs.

The reflux column may be packed, for example, with helices, Raschigrings or the like. The reflux column may also be regulated in such a waythat part of the fatty acids are allowed to distil off.

After heating, any unchanged fatty compounds in the reaction mixture maybe dissolved out by a suitable solvent, for example, alcohol.Alternatively, the reaction mixture may be distilled, if desired, undervacuum, to remove unchanged fatty materials. The residue after solventtreatment or distillation is the desired product. Preferably thereaction mixture is filtered, washed with hot water to remove thecatalyst and dried under vacuum before solvent treatment ordistillation.

The distillate or solvent extract may be reused for a further reactionsince it consists substantially of unchanged starting material. Ifthereaction is allowed to proceed to a stage where only a smallproportion of unchanged starting material is contained in the reactionmixture there may be no need to remove the unchanged starting material.

The residue, obtained as described above. forms the main product. Whenthe starting material contains unsaturated fatty anhydrides the productshows better drying properties than the corresponding triglycerides anddecreased volatility and increased viscosity when compared with thefatty anhydrides forming the starting material. The changes in theseproperties become more evident with increased time or temperature ofheating. The analytical figures show the formation of a substantialproportion of unsaponifiable matter which is different from known fattyketones. This unsaponifiable matter is mainly responsible for the gooddrying properties and when isolated shows outstanding film formingproperties.

The invention also includes the novel condensation products obtained bythese processes as such, or in admixture with unchanged fatty anhydridesand acids.

The condensation products of the invention are characterised by asubstantial amount, preferably at least 40%, of unsaponifiable matter, alow acid and saponification value, an increased iodine value, accordingto Wijs, as compared to the starting material and a high mean molecularweight. The mean molecular weight of the unsaponifiable matter isroughly in accordance with, or higher than, the calculated molecularweight of a theoretical condensation product of three molecules of fattyacid. The condensation product has drying properties when the iodinevalue (determined according to Wijs method) is 100 or higher.Condensation products containing from 20 to 30% of unsaponifiable matterhave been found useful for certain purposes whilst for other purposescondensation products containing from 30 to 40% of unsaponifiable matterare valuable.

The condensation products have a molecular structure which contains atleast three alkyl chains. The preferred products are those in which thealkyl chains are those of unsaturated acids derived from fatty oils, orare shorter than the chains of unsaturated acids derived from fatty oilsby the loss of one carbon atom in the condensation reaction.

The invention also includes the use of the above mentioned productshaving an iodine value (determined by Wijs method) of 100'or higher, toreplace drying materials, such as drying oils, oleo resinous varnishes,or alkyd resins in the paint, varnish, linoleum and allied industries.

The new products may be mixed with the usual siccati ves based oncobalt, lead or manganese and may be diluted with turpentine, mineralspirits or othervolatile solvents to the desired viscosity.

Zinc white enamels prepared from the condensation products showed nosigns of livering.

The invention will now be illustrated by the following examples. In theexamples the temperatures quoted are those of the metal bath surroundingthe reaction vessel, except when otherwise indicated. The temperaturewithin the reaction mixture was lower, by about 20 and C. during theinitial stages and by about 10 C. during the final stages of thereaction.

Example 1 100 grams of groundnut fatty acid anhydride (acid value 101.3;saponification value 199.8; iodine value 101.4; unsaponifiable matter4%) and 2 grams of finely pulverized boric acid anhydride were heatedover 3 hours up to a temperature of 290 C. in an evacuated flask fittedwith a reflux cooler. After the heating had been continued at thistemperature for 4% hours under reflux conditions the reflux conduit wasdisconnected and the heating was continued for a further /2 hour at thesame temperature whilst the distillate was collected in a receiver.Throughout the experiment the apparatuswas evacuated to about 3 mms.mercury pressure. The treatment gave the following materials:

Grams Residue (inclusive of catalyst) 83.04 Distillate 6.25 Fatty matterin the conduits 3.35 Water 6.46 Carbon dioxide 2.70 Loss 0.20

The residue was found to possess very good film-building properties and,after the solid catalyst had been filtered off and 0.3% lead and 0.02%manganese had been added as naphthenates, became dry to the touch in 8hours and practically non-tacky in 17 hours. Analysis of the residuegave an acid value of 4.9, a saponification value of 26.9, an iodinevalue of 115.4 and 96.4%- of unsaponifiable matter. The distillateconsisted of fatty acids and had an acid value of 133.7, a saponification value of 209.3 and an iodine value of 92.4.

Example 2 66 grams of groundnut fatty acid anhydride and 34 grams oflinseed oil fatty acid were heated with 2 grams of boric acid over 3hours up to 290 C. and the mixture was heated for 4 hours at 290 C.undera vacuum of 3 mm. mercury under reflux conditions. The refluxconduit was disconnected for the last 10 minutes of the heating so thatthe distillate collected in a receiver. The residue, weighing 77.5 gramswithout catalyst, was gelatinous, but when boiled with water became aviscous liquid once more. It had an acid value of 9.6, a saponificationvalue of 43.9, an iodine value of 154.0 and contained 92.6% ofunsaponifiable matter. The viscous liquid product was diluted with halfits weight of a solvent consisting of 1 part of turpentine to 1 part ofmineral spirits and siccativated with lead/manganese naphthenate. Theresultant material dried as a thin film in 2% hours.

Example 3 38.4 grams of groundnut fatty acid ketone obtained fromgroundnut fatty acids with an iodine value of 96.8 and 41.6 grams ofgroundnut fatty acid anhydride, obtained from the same groundnut fattyacids by boiling with acetic acid anhydride in the presence of a littlephosphoric acid, were heated with 1.6 grams boric acid over 3 hours upto 290 C. in an evacuated reflux apparatus and were then heated at 290C. for a further 5 hours. During the last half hour the reflux conduitwas disconnected and the condensate was collected in the receiver. Theresidue was 66.9 grams after removing the boric acid and had an acidvalue of 8.0, a saponification value of 21.8, an iodine value of 155.6.When siccativated the product was dry to the touch in 5 days andcompletely dry in about 7 days.

We claim:

1. A process for preparing condensation products, which comprisesheating an anhydride of the formula R.C0.0.CO.R' where R and R eachconsists of an unsubstituted long chain hydrocarbon radical, at atemperature of 180 to 300 C., in the presence of a catalyst selectedfrom the group consisting of boric acid, boric oxide, ammoniumpentaborate, trimethyl borate, triethyl borate, m-annitol borate and themixed anhydrides of boric acid and fatty acid, until the reactionmixture contains at least 40% by weight of unsaponifiable matter derivedfrom the anhydride and of mean molecular weight at least three timesthat of an acid of which the anhydride is a derivative, the heatingbeing carried out under such conditions that water liberated during thereaction is removed from the reaction zone as it is formed but the lossof the major part of the anhydride is avoided.

2. A process for preparing condensation products, which comprisesheating an anhydride of the formula R.C0.0.CO.R where R and R eachconsists of an unsubstituted long chain hydrocarbon radical, at atemperature of 180 to 300 C., in the presence of a catalyst selectedfrom the group consisting of boric acid, boric oxide, ammoniumpentaborate, trimethyl borate, triethyl borate, mannitol borate and themixed anhydrides of boric acid and fatty acid, until the reactionmixture contains at least 40% by weight of unsaponifi-able matterderived from the anhydride and of mean molecular weight at least threetimes that of an acid of which the anhydride is a derivative, theheating being carried out under such conditions that water liberatedduring the reaction is removed from the reaction zone as it is formedbut the loss of the major part of the anhydride is avoided, and thereaction mixture being kept at 240 to 300 C. at least during the latterpart of the reaction.

3. A process according to claim 2 wherein any sub- 6 stantial amounts ofuncondensed fatty material are ultimately removed.

4. A process according to claim 1 wherein the treated anhydride containsfrom 20 to 52 carbon atoms.

5. A process according to claim 1 wherein the treated anhydride containsfrom 36 to 44 carbon atoms.

6. A process according to claim 2 wherein R and R are identicalunsaturated hydrocarbon radicals containing from 9 to 25 carbon atoms inchain formtaion.

7. A process according to claim 2 wherein R and R are identicalunsaturated hydrocarbon radicals containing 17 to 21 carbon atoms inchain formation.

8. A process for preparing condensation products, which comprisesheating an anhydride of the formula R.C0.0.CO.R where R and R eachconsists of an unsubstituted long chain hydrocarbon radical, at atemperature of to 300 C., in the presence of a boric acid catalyst,until the reaction mixture contains at least 40% by weight ofunsaponifiable matter derived from the anhydride and of mean molecularweight at least three times that of an acid of which the anhydride is aderivative, the heating being carried out under such conditions thatWater liberated during the reaction is removed from the reaction zone asit is formed but the loss of the major part of the anhydride is avoided.

9. A process for preparing condensation products, which comprisesheating an anhydride of the formula R.C0.0.CO.R where R and R eachconsists of an unsubstituted long chain hydrocarbon radical, at atemperature of 180 to 300 C., in the presence of a boric oxide catalyst,until the reaction mixture contains at least 40% by weight ofunsaponifiable matter derived from the anhydride and of mean molecularweight at least three times that of an acid of which the anhydride is aderivative, the heating being carried out under such conditions thatwater liberated during the reaction is removed from the reaction zone asit is formed but the loss of the major part of the anhydride is avoided.

References Cited in the file of this patent UNITED STATES PATENTS1,987,559 Hintermaier Jan. 8, 1935 2,251,550 Lieber Aug. 5, 19412,411,567 Fisher Nov. 26, 1946 2,465,073 Dombrow et al Mar. 22, 19492,465,337 Miller et al Mar. 29, 1949 2,513,825 Sorensen July 4, 19502,544,365 Sorensen Mar. 6, 1951 2,730,530 Ohlson et-al Jan. 10, 1956OTHER REFERENCES Man et al.: J. Am. Chem. Soc., vol. 72, pp. 3294-5(1950).

1. A PROCESS FOR PREPARING CONDENSATION PRODUCTS, WHICH COMPRISES HEATING AN ANHYDRIDE OF THE FORMULA R.CO.O.CO.R'' WHERE R AND R'' EACH CONSISTS OF AN UNSUBSTITUTED LONG CHAIN HYDROCARBON RADICAL, AT A TEMPERATURE OF 180 TO 300*C., IN THE PRESENCE OF A CATALYST SELECTED FROM THE GROUP CONSISTING OF BORIC ACID, BORIC OXIDE, AMMONIUM PENTABORATE, TRIMETHYL BORATE, TRIETHYL BORATE, MANNITOL BORATE AND THE MIXED ANHYDRIDES OF BORIC ACID AND FATTY ACID, UNTIL THE REACTION MIXTURE CONTAINS AT LEAST 40% BY WEIGHT OF UNSAPONIFIABLE MATTER DERIVED FROM THE ANHYDRIDE AND OF MEAN MOLECULAR WEIGHT AT LEAST THREE TIMES THAT OF AN ACID OF WHICH THE ANHYDRIDE IS A DERIVATIVE, THE HEATING BEING CARRIED OUT UNDER SUCH CONDITIONS THAT WATER LIBERATED DURING THE REACTION IS REMOVED FROM THE REACTION ZONE AS IT IS FORMED BUT THE LOSS OF THE MAJOR PART OF THE ANHYDRIDE IS AVOIDED. 